[need help again] plane won't pitch down

[Konohanin]

i am currently building my first plane, it doesn't look to bad for the stage of progression, but controlling it seems off: it had a tendency to pitch up (mostly fixed) and it when rolling, sometimes it violently rolls in the opposite direction before slowly rolling to the intended side (might be because i connected some nodes wrong), but the main problem lies in the pitch, as despite the control surfaces motion changing, the pitch doesn't. pitching up works just fine though

[ElfBossHogg]

Are you using a gyro in the build of your plane?

[Ra-Ra-Rasputin]

The common issue with planes is often building them with either negative lift potential or even downward facing thrust, or the exact opposite. This is often because people try to imitate real life planes without understanding that their control and lift profile is often caused by minutia or kinematic parts such as flaps.

Also should note like ElfBossHogg noted that curiously enough, the gyro is explicitly for the helicopter. It is completely unsuited for a plane, and in fact, planes don't really need one as strange as that sounds.

Being unable to pitch down generally means that your control surfaces are either in a position where they don't get enough purchase (or at all, if you've placed them anywhere near center of mass) or you have constant positive lift and don't have the aerodynamics to counteract it. Hard to say without actually having hands on time with your plane.

[Konohanin]

controls work just fine when below 50-ish thrust (of 130) and i'm not using a gyro.
i am not sure whether it is because of the aerodynamics of the design (if that even plays a role) or bad placement, but for some reason maneuverability differs greatly depending on airspeed. beyond a certain airspeed (i think 400-500 km/h) the control surfaces lose their ability to make the plane pitch downward and are only able to cancel any pitch going up, but i still retain the ability to pitch up. the plane itself has a tendency to pitch up by itself so it really might be the hull that's causing the issue
my knowledge of hydro/ aerodynamics is let's say 'limited' so i might be missing something obvious. should i upload the current version of it for you to inspect?

[PenguinO]

Dev broke those control surface last year.
My best solution would be "spamming the control fins", use the small ones (1x1x1)
and use at least LENGHT+WIDTH+HEIGHT (block count) for ailerons, elevators and rudders sum together.
This way you should be able to retain control at higher airspeed.

[Ra-Ra-Rasputin]

You can use fin rudders instead. They're extremely powerful and more powerful at higher speeds.

[Konohanin]

you were right about rudders
though it still leaves a little bit to be desired, pitch now works well enough at even maximum airspeed, though pitching up still works best for a loop
i had been using fin rudders for yaw which worked really well, but i didn't consider them for other uses
i'll now improve the roll with fin rudders and the plane is expected to work like expected, thanks